1. Field of the Invention
The present invention relates to the field of liquid crystal display technology, and in particular to a fanout zone structure of a liquid crystal display.
2. The Related Arts
Liquid crystal displays have a variety of advantages, such as thin device body, low power consumption, and being free of radiation, and are thus widely used. Most of the liquid crystal displays that are currently available in the market are backlighting liquid crystal displays, which comprise a liquid crystal panel and a backlight module. The operation principle of the liquid crystal panel is that, with liquid crystal molecules interposed between two parallel glass substrates, a driving voltage is applied to the two glass substrates to control the rotation direction of the liquid crystal molecules in order to refract out light emitting from the backlight module for generating images. Since the liquid crystal panel does not emit light by itself, light must be provided from the backlight module in order to normally display images. Thus, the backlight module is one of the key components of a liquid crystal display. The backlight modules can be classified in two types, namely a side-edge backlight module and a direct backlight module, according to the position where light gets incident. The direct backlight module comprises a light source, such as a cold cathode fluorescent lamp (CCFL) or a light-emitting diode (LED), which is arranged at the backside of the liquid crystal panel to form a planar light source directly supplied to the liquid crystal panel. The side-edge backlight module comprises an LED light bar, serving as a backlight source, which is arranged at an edge of a backplane to be located rearward of one side of the liquid crystal panel. The LED light bar emits light that enters a light guide plate (LGP) through a light incident face at one side of the light guide plate and is projected out of a light emergence face of the light guide plate, after being reflected and diffused, to form a planar light source for the liquid crystal display panel.
With the development of the liquid crystal display technology, users have severer and severer requirements for the performance and outside looking of the liquid crystal displays, wherein the distance from an effective displaying zone of a liquid crystal display panel to an edge of the panel (namely bezel width) is made increasingly smaller. However, due to various factors, such as polyimide (PI) coating processes (alignment film coating processes), it is generally hard to make the bezel width smaller. In the known techniques, to reduce the bezel width, in the color filter substrate portion, a photo spacer (PS) layer is used to prevent outward flowing of polyimide and, in the array substrate portion, two layers of metal films are stacked in the circumference to form a step for preventing outward flowing of polyimide. However, in a fanout zone (which is the area where display zone signal lines are connected to drivers), a plurality of signal lines is formed and the signal lines themselves need two layers of metal films so that it is not possible to stack metal films in the fanout zone for forming a step to prevent outward flowing of polyimide.